The present invention relates to a transfer mechanism and method for efficiently transferring blow-molded articles from a vertically-disposed wheel blow molding machine to a horizontally-disposed takeaway conveyor, and more particularly, the present invention relates to a method and apparatus in which blown articles are released in free fall from a wheel blow molding machine and are positioned in an orderly uniform manner on a takeaway conveyor for transport to further operations, such as trimming.
One type of blow molding machine utilized to manufacture blow molded containers is a wheel blow molding machine which is vertically disposed and rotates about a horizontal axis. An example is illustrated in FIG. 1 of U.S. Pat. No. 5,681,597 issued to Aguilar et al. and by the discussion provided in the Aguilar patent on column 2, line 52 to column 3, line 23. To this end, the blow molding machine has a plurality of molds positioned in a circular array following a circular path of motion. Each mold has a pair of mold halves which open to receive an extruded hollow parison, which close thereon so that the parison can be blown into conformance with the cavity defined by the mold, and which thereafter, open to release the blown article. All of these operations occur as the wheel continuously rotates at a constant speed, thereby forming and releasing blown articles in a continuous manner.
As best disclosed in the background section of U.S. Pat. No. 3,981,667 issued to Bilodeau on column 1, lines 15-30, it is known to discharge blown articles from wheel blow molding machines by gravity ejection onto a chute feeding a conveyor which supplies a surge hopper. The randomly arranged articles located in the hopper are then manually placed in a uniform manner onto other conveyors, or like apparatus, for transport to further processing stations, such as for trimming.
The above referenced Aguilar and Bilodeau patents disclose the use of automated takeout apparatus for increasing the speed of transfer of blown articles from a wheel blow molding machine to a downstream processing station and for eliminating the need of manually placing blown articles in a required uniform position on a takeaway conveyor. Known takeout apparatus includes vacuum pickup heads, star wheels, or buckets for individually picking one blown article per mold from the wheel blow molding machine and for placing the blown article in a uniform manner on a takeaway conveyor.
A further effort to increase the rate of forming blow molded articles is disclosed by U.S. Pat. Nos. 3,432,586 issued to Stenger and 3,862,698 issued to Hafele. To this end, a blown article is formed in a blow mold from a single parison and comprises a pair of containers integrally connected by a ring of scrap or flash material. The blown article is trimmed to remove the scrap/flash material and to separate the containers into two identical separate container bodies. This concept can be utilized to effectively double the output of bottles that can be formed during each revolution of a wheel blow molding machine.
It is also known to simultaneously extrude multiple separate parisons within a blow mold to simultaneously form multiple separate blown articles in each mold. See, for instance, U.S. Pat. Nos. 5,551,862 issued to Allred, Jr., 4,861,542 issued to Oles et al., and 3,802,823 issued to Doughty et al. Taking this concept one step further, as illustrated in FIG. 4 of the present application, a blow mold can be provided to accept multiple parisons and to utilize each parison to form multiple blown bottles. For instance, it is contemplated to use the mold illustrated in FIG. 4 of the present application to form four bottles per mold in a two by two manner, and to utilize the mold on a vertically disposed wheel blow molding machine having twentyfour identical such molds for forming approximately 500 to 850 bottles per minute.
The increased rate of forming bottles in a wheel blow molding machine and the use of multiple parisons for forming multiple blown articles in each mold significantly complicates the task of removing blown articles from a wheel blow molding machine and placing the blown articles in a uniform position on a horizontally disposed takeaway conveyor. In addition, vacuum and/or mechanical pick and place machines have relatively complicated structures and are relatively expensive to build and/or purchase. They require frequent maintenance and are prone to experiencing mechanical and pneumatic failures. The downtime of the pick and place machines can significantly reduce the overall rate of manufacture of containers. Thus, a more efficient and cost-effective transfer mechanism for transferring containers from a vertically-disposed wheel blow molding machine to a horizontally-disposed takeaway conveyor is desired.
While various ones of the takeout and transfer mechanisms disclosed in the above referenced patents may function satisfactorily for their intended purposes under certain circumstances, there is a need for a takeout and transfer apparatus and method for efficiently transferring blow-molded articles, two at time, in a continuous manner from a vertically-disposed wheel blow molding machine to a horizontally-disposed takeaway conveyor. The apparatus should have a relatively simple construction which requires a minimum of downtime, if any, and which is cost-effective to manufacture and/or purchase. The apparatus and method should be capable of reliably removing 500 to 850 blow molded bottles per minute from a wheel blow molding machine and placing the bottles in an orderly manner in a required uniform position on a horizontally disposed conveyor. In addition, the apparatus and method should be capable of handling multiple separate blown articles released simultaneously from a blow mold.
With the foregoing in mind, a primary object of the present invention is to provide a blown article takeout and transfer system which is capable of handling multiple simultaneously released blown articles from a vertically-disposed wheel blow molding machine and transferring the articles in a uniform orderly manner to a horizontally-disposed conveyor.
Another object of the present invention is to provide a high-speed bottle transfer system capable of transferring at least about 500 to about 850 bottles per minute from a vertically-disposed wheel blow molding machine to a horizontally-disposed conveyor.
A further object of the present invention is to provide a high-speed bottle transfer system which requires no significant preventative maintenance and which experiences minimal, if any, downtime.
A still further object of the present invention is to provide a novel method of transferring blow molded articles from a vertically-disposed wheel blow molding machine to a horizontally-disposed takeaway conveyor.
More specifically, the present invention provides an apparatus for use with a vertically disposed wheel blow molding machine to receive blown plastic articles from the wheel blow molding machine and to transfer the blown articles in a uniform and orderly manner to a downstream blown article processing station, such as a trimmer. The apparatus includes a powered takeaway conveyor for transporting blown articles from the wheel blow molding machine. The takeaway conveyor has an inclined receiving end and a substantially horizontally disposed transporting section extending from the receiving end. The receiving end is located underneath the wheel blow molding machine and receives blown articles released in a free gravitational vertical-fall from the wheel blow molding machine. A powered endless positioning belt is located above the takeaway conveyor and extends a spaced distance from the inclined receiving end of the takeaway conveyor for confining the blown articles falling from the wheel blow molding machine on the inclined receiving end of the takeaway conveyor so that the blown articles are positioned on the takeaway conveyor in a controlled uniform manner.
According to another aspect of the present invention, a method is provided for removing blown articles from a vertically disposed wheel blow molding machine and for placing the articles in a controlled uniform manner on a takeaway conveyor. Blown articles are released from a vertically-disposed wheel blow molding machine so that the blown articles exit the blow molding machine in a free gravitational vertical-fall. The free falling articles are received on an inclined end of a powered takeaway conveyor located underneath the wheel blow molding machine. Preferably, the blown articles are released two at a time from the wheel blow molding machine and are received two at a time on the takeaway conveyor. The blown articles are confined on the inclined end of the takeaway conveyor by a powered endless positioning belt located above the takeaway conveyor and extending along the inclined end at a spaced distance therefrom such that the blown articles, as received, are located between and are engaged by the inclined end and the positioning belt to position the blown articles on the takeaway conveyor in a controlled uniform manner. The blown articles are transported on the takeaway conveyor from the wheel blow molding machine to a downstream blown article processing station, such as trimmer.